1. Field of the Invention
This invention pertains to surgical instruments, and more particularly it pertains to surgical instruments that apply heat or energy to achieve hemostasis or coagulation for the sealing of blood vessels during the surgical operation.
2. Description of the Prior Art
During a surgical operation, a major portion of the total time required is used for controlling bleeding. Such bleeding obscures the surgeon's vision, reduces his surgical precision and often makes necessary the following of slow and elaborate procedures. Typically, each bleeding vessel must be grasped in a surgical clamp to stop the flow of blood. The tissue and vessel within each clamp is then tied with pieces of fine thread. Such ligated masses of tissue subsequently die and decompose, retarding healing and encouraging infection.
Heating of a cutting instrument to provide simultaneous hemostasis is disclosed in U.S. Pat. No. RE. 29,088 which issued on Jan. 11, 1977, U.S. Pat. No. RE. 30,190 which issued on Jan. 15, 1980, U.S. Pat. No. 4,089,336 which issued on May 16, 1978, U.S. Pat. No. 4,091,813 which issued on May 30, 1978, U.S. Pat. No. 4,185,632 which issued on Jan. 29, 1980, and U.S. Pat. No. 4,481,057 which issued on Nov. 6, 1984. While a heated cutting instrument of the type disclosed in such patents provides satisfactory hemostasis for smaller blood vessels, it does have difficulty sealing larger vessels.
Electrosurgery provides an alternative method of bleeding control, coagulation, or hemostasis, as well as providing a cutting capability. An electrical current flows through a circuit that begins at a high-frequency oscillator within an electrosurgical unit, goes through an active cable and an active electrode to the patient, and then returns from the patient by way of a dispersive electrode and a cable to the electrosurgical unit. The dispersive electrode has a relatively large contact area to prevent burns to the patient's body, while the relatively small contact area between the tissue and the active electrode tip causes a concentration of current (high current density) that heats the tissue at this point. By raising the temperature of the tissue or cells to the point of changing the protein into coagulum, coagulation or hemostasis is accomplished. Electrosurgical instruments that can produce coagulation are disclosed in U.S. Pat. No. 4,112,950 which issued Sept. 12, 1978, to Pike; U.S. Pat. No. 4,311,145 which issued Jan. 19, 1982, to Esty et al.; and U.S. Pat. No. 4,427,006 which issued Jan. 24, 1984, to Nottke.
Surgical and hemostatic scalpels along with electrosurgical units have been available in operating rooms. Hertofore, scalpels and electrosurgical active electrodes have been separate instruments mounted in separate handles. To use a scalpel and an electrosurgical active electrode sequentially during an operation required excessive handling, changing back and forth from one instrument to the other. This is both time consuming and distracting for the surgeon. Furthermore, after an operation the scalpel blade and the electrode are changed individually in their respective handles.